28 PRELIMINARY NOTICE ON THE 



sufficient for the production of 677 to 80- tons of wrought iron per 

 annum ; or on the more economical system for the out-turn annually 

 of say 1,000 tons of bar iron, about 12'5 square miles of forest would 

 be required, that is to say, an area included in a square of 3' 6 miles 

 on each side. In other words, for the annual supply of charcoal for 

 1,000 tons of wrought iron, a circle of 4 miles diameter would suffice. 



To increase this produce of course the area of supply should be 

 proportionally increased. Thus, for the annual production of 10,000 

 tons of iron, an area of 125 square miles would be necessary, an area 

 comprised within a circle of about 12 '5 miles in diameter. In this case, 

 supposing the site of the manufacture to be placed near the centre of 

 the supplying area, the distance from which the fuel would have to be 

 brought would be not more than 7 miles. Again, if we take the 

 extreme limit from which fuel might be carried with profit, as about 10 

 miles on all sides of the furnace, we shall have a circle of 20 miles in 

 diameter, which, allowing something for the clearances which must exist, 

 will give us about 300 square miles, affording charcoal sufficient for 

 the manufacture of 24,000 tons of iron annually. 



These calculations are necessarily based on the supposition, that the 

 produce of each acre or square mile of the area will be nearly alike, and 

 also, that the whole of the estimated area is under forest. There are 

 few, if any, places in the country, where such conditions will be found 

 to exist ; and bearing in mind the necessity for open spaces for the works 

 themselves, the amount of ground which must inevitably be given up to 

 sites for houses and to ordinary cultivation in the vicinity of such large 

 works, I think it would be very unsafe to anticipate that, mthin a circle 

 of any given radius, in any desirable locality for such undertakings, there 

 would be found more than one-half of the entire included area yielding 

 good forest return : that is, on the same data as are taken above, a circle 

 of 10 miles radius would yield a supply of fuel annually sufficient for the 

 production of 1 2,000 tons of wrought iron ; but even this would repre- 

 sent about 2-50 tons per week ; and is, in any case, a larger amount 



